Many methods are known for forming the electrical interconnections between an integrated circuit and the supporting substrate. Tape automated bonding (TAB) is one commonly known method for forming these such electrical interconnections. A TAB tape is provided which is made up of many identical electrical lead configurations sequentially patterned along the tape.
The electrical lead pattern comprises many individual long, slender leads attached to, and extending radially inward from, the perimeter of the TAB tape material. The integrated circuit is provided within the center of the TAB tape and gang bonded to each of the electrical leads. After bonding between the integrated circuit and electrical leads is complete, the integrated circuit is excised from the TAB tape. The integrated circuit is subsequently mounted on an appropriate printed substrate, if this has not already been done, and accordingly bonded to the substrate.
The integrity of the individual integrated circuit assemblies must be maintained throughout processing, but particularly during the period after the integrated circuit has been bonded to the electrical leads but not yet excised from the TAB tape. During this period, the TAB tape, integrated circuit and patterned slender electrical leads must be maintained in a substantially planar manner to ensure the integrity of the assembly for subsequent attachment of the integrated circuit to an appropriate substrate. Therefore, generally, a carrier ring or other device which fits around the perimeter of the TAB tape to retain the integrated circuit and electrical leads is utilized. The carrier is typically formed from a molded plastic or other material which is relatively inexpensive, yet durable. After molding, the carrier assembly having the integrated circuit and leads is fed into an assembly machine which then excises the integrated circuit and leads from the carrier and mounts the integrated circuit onto an appropriate printed circuit.
During assembly and transport, these carrier assemblies are generally stacked vertically or horizontally and individually fed into the assembly machine. However, this method results in several disadvantages. Firstly, complex packaging and feed systems are required to handle the individual carrier units, since the individual units are not amenable to use with conventional tape and reel packaging methods. Secondly, it is expensive to package each unit individually. Lastly, there is added waste and bulk as a result of the individual packaging for each unit.
It is desirable therefore to provide a means for packaging these carrier assemblies which is amenable to the automatic feed handling systems used to attach the integrated circuit within the carrier unit to a printed circuit board, wherein the carrier assemblies would be provided in a continuous manner. It is also desirable that the method for packaging be simplistic in design and relatively inexpensive. Lastly, it is desirable that the packaging method not generate undue waste.